1. Field of the Invention
The disclosures herein relate to the control of width of correction patterns used for the correction of color alignment in image forming apparatuses.
2. Description of the Related Art
In recent years, color image forming apparatuses have been widely used as apparatus for printing images. Color image forming apparatuses form a transfer color image on a transfer belt by superimposing toner images in respective colors created by electrostatic imaging processes. This transfer color image is then transferred onto a transfer sheet. In such color image forming apparatuses, a tandem-type configuration is widely used.
In color image forming apparatuses having the above-noted configuration, toner images in respective colors may not be aligned at the correct position due to error in spacing between the axes of respective photoconductive drums, error in parallelism between the respective photoconductive drums, error in the position of a deflecting mirror for deflecting a laser beam in a light emission unit, error in the write timing of an electrostatic image on the photoconductive drums, and so on. This gives rise to the problem of color misalignment. There is thus a need to correct the misalignment of color toner images.
Japanese Patent Application Publication No. 2005-202432 discloses different operation modes, which include a mode in which multiple different processes are performed, a mode in which a print time is shortened, and a mode in which print quality is improved. A user is given a choice as to which mode is to be used. Positional alignment is then performed in conformity with the mode of choice.
It is necessary to improve the accuracy of correction of color misalignment occurring due to various factors in order to obtain a high-quality color image in a tandem-type color image forming apparatus.
Accordingly, there is a need for an image forming apparatus in which the accuracy of correction of color misalignment is improved. There is also a need for a method of controlling the width of correction patterns.